This issue was discussed in the review thread for:
The issue is important to fix as a part of the Test Stabilization project.
Please, see my reply to Dan below.
Some comments below.
On 2/4/14 7:48 AM, Daniel D. Daugherty wrote:
> On 2/4/14 4:13 AM, email@example.com wrote:
>> Please, review the fix for:
>> Open webrev:
> No comments.
> No comments beyond David's tweak to the comment.
Will fix it before push.
> For future work...
> Looks like these VM ops also need the liveness check on the
> target JavaThread:
> JvmtiEnv::GetStackTrace() looks like it has the same
> is_thread_fully_suspended() flaw...
I know about this.
There are even more issues:
I'll check if we can use an existing bug to add this extra request.
Otherwise, will file new one.
>> This is the second round of review for this issue.
>> But it was decided that the JDK-8032223 must be used to cover it instead of the JDK-6471769.
>> The 8032223 was initially closed as a dup of 6471769 but it has been re-open now.
>> There is a general issue in the suspend equivalent condition mechanism:
>> Two subsequent calls to the JvmtiEnv::is_thread_fully_suspended() may return different results:
>> - 1-st: true
>> - 2-nd: false
>> This suspend equivalent issue is covered by another bug:
>> The bug to fix in this review is a specific manifestation of the 6280037
>> in the JVMTI GetFrameCount() that has a major impact on the SQE nightly.
>> It is on the Test Stabilization radar as well as the 6280037.
>> There are many tests intermittently failing because of this.
>> I've also decided to fix the same issue in the JVMTI GetFrameLocation() as well.
>> The JVMTI GetFrameCount() spec tells:
>> "If this function is called for a thread actively executing bytecodes (for example,
>> not the current thread and not suspended), the information returned is transient."
>> So, it is Ok to call the GetFrameCount() for the non-suspended target thread.
>> To achieve safety, the frame count for non-suspended threads is calculated at a safepoint.
>> It should be Ok and more safe to do the same for suspended threads as well.
>> There should be no big performance impact because it is already on a slow path.
>> It is still important to avoid safepointing when the target thread is current.
>> The bug 6280037 should go out of the Test Stabilization radar (remove the svc-nightly label)
>> as the most of the impacted tests must be covered by the 8032223.
>> In progress:
>> - nsk.jvmti, nsk.jdi, nsk.jdwp
>> - JTreg com/sun/jdi